1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method. Examples of substrates to be processed include semiconductor wafers, substrates for liquid crystal display devices, substrates for plasma displays, substrates for FEDs (field emission displays), substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, and substrates for photomasks, ceramic substrates, substrates for solar cells.
2. Description of Related Art
US2013/0152971 A1 discloses a rotating type substrate holding/rotating device that includes a rotary table rotatable around a rotational axis aligned with a vertical direction, a rotation driving unit that rotates the rotary table around the rotational axis, and a plurality (for example, four) of holding pins disposed on the rotary table and horizontally positioning a substrate across a prescribed interval from a front surface of the rotary table.
The plurality of holding pins include fixed pins that are immovable with respect to the rotary table and movable pins that are movable with respect to the rotary table. Each movable pin has a contacting portion arranged to be rotatable around a rotational axis coaxial to a central axis of the movable pin and arranged to contact a peripheral end edge of the substrate. By rotation of the contacting portion, the contacting portion is displaced between an open position that is far apart from the rotational axis and a hold position that has approached the rotational axis. A pin driving magnet is coupled to a rotating shaft of the contacting portion.
Switching between opening and closing of the movable pins is performed using an elevated/lowered magnet disposed below the rotary table (magnet switching type). A magnet elevating/lowering unit is coupled to the elevated/lowered magnet. When the elevated/lowered magnet is at a prescribed lower position, the elevated/lowered magnet does not face the pin driving magnets and an external force, which urges the movable pins to the hold position, does not act on the movable pins. Therefore, when the elevated/lowered magnet is at the lower position, the movable pins are held at the open position. On the other hand, when the elevated/lowered magnet is at a prescribed upper position, the movable pins are held at the hold position by a magnetic attractive force between the elevated/lowered magnet and the pin driving magnets.